Orthosis for gait modulation

ABSTRACT

A functional electrical stimulation (FES) orthosis, including: a frame, an inner layer coupled to an inner surface of the frame, an electrode base, and a connector assembly. The frame is configured to substantially envelop a limb, and includes a retention portion configured to retain the frame about the limb, and a mounting portion configured to be coupled to an electrical stimulator. The electrode base is coupled to the inner layer, and is configured to couple a surface electrode to the inner layer. The frame and the inner layer are configured such that the electrode base is disposed at a predetermined position relative to the limb. The connector assembly is configured to electrically couple the stimulator to the electrode base. At least a portion of the connector assembly is disposed within a connector opening defined by the frame.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/036,256, now U.S. Pat. No. 8,209,036, entitled “Orthosis for a GaitModulation System,” filed Feb. 28, 2011, which is a continuation of U.S.application Ser. No. 11/380,430, now U.S. Pat. No. 7,899,556, entitled“Orthosis for a Gait Modulation System,” filed Apr. 27, 2006, whichclaims priority to U.S. Provisional Patent Application Ser. No.60/736,858, filed Nov. 16, 2005, the entirety of which is incorporatedherein by reference in its entirety.

BACKGROUND

The present invention relates to gait modulation systems usingfunctional electrical stimulation (FES), and more particularly, to anFES orthosis for such an FES orthosis and method of using such gaitmodulation systems.

It is known that pathologies of the neuromuscular system due to diseaseor trauma to the central nervous system, such as stroke, spinal cordinjury, head injury, cerebral palsy and multiple sclerosis, can impedeproper limb functioning of the hands or legs. Gait, the biomechanicaldescription of walking, can suffer static and dynamic parametervariations due to neuromuscular impairments, which cause non-symmetricalwalking, reduced walking speed and reduced walking stability.

Drop foot describes the gait attributable to weak or uncoordinatedactivation of the ankle dorsi-flexors due to disease or trauma to thecentral nervous system. Patients suffering from drop foot tend to dragthe foot during the swing phase of walking and usually try to compensatefor this dragging by hiking their hip or swinging it in a circularmotion. These patients tend to have impaired stability, are prone tofrequent falls, and their walking movements are unaesthetic and energyconsuming.

However, limb muscles can generally be activated with FES. In FES,precisely timed bursts of short electrical pulses are applied to motornerves, to generate muscle contraction, which can be applied toenhancing limb function.

Although more than four decades have elapsed since the firstneuroprosthetic system was proposed, much room remains for improving thetechnological quality of such systems. This is reflected, inter alia, bythe relatively small percentage of potential users who regularly don aneuroprosthetic device to compensate for limb and gait problems, andparticularly, a drop foot problem. These systems suffer from manydrawbacks that prevent them from being widely used by potentialpatients.

When problems with arm movement or gait result from stroke or braininjury, they are often accompanied by hand impairment on the same sideof the body as the limb on which the FES orthosis is donned. Thus, thedonning action must often be carried out using solely thecontra-lateral, unaffected hand. Moreover, the posture of the plegiclimb is often problematic, especially in cases where spasticity resultsin reduced voluntary movements and also in a limited passive range ofmotion of the limb joints. Consequently, objective biomechanicalproblems exist in donning the orthotic device and in locating theelectrodes in exact position onto the limb. Prior art neuroprostheticdevices differ in that they fail to enable facile, quick and accuratedonning of the device by an impaired patient using a single hand, andparticularly, when even that hand is shaky or otherwise unstable.

Prior art external FES devices typically utilize a stimulator unit thatis physically separate from the FES orthosis, to create and control theelectrical pulses being applied to motor nerves. The external stimulatorunit, which is connected to the FES orthosis by several electricalwires, is located on the body of the user, and is typically attached tothe belt of the user. These devices can be inconvenient for the user.Particularly cumbersome is the wiring, which is usually arranged to runalong the leg under the clothing to connect the device components.

In additional, neuroprostheses require precise fitting for eachindividual patient, in an optimal fashion, by exactly identifying thestimulation points that cause contraction of the muscles, andpositioning and locking the electrodes thereto. Consequently, use of theknown devices, which are configured and dedicated to the anatomy andneeds of a particular individual, is limited to that individual only,and further requires considerable expertise to reconfigure the devicefor transfer to another patient.

U.S. Pat. Nos. 5,643,332 and 5,814,093 to Stein disclose an assembly forfunctional electrical stimulation during movement, including a band,mountable on the leg, carrying all of the components of the assembly toprovide a self-contained unit. The components comprise: electrodes forstimulating a leg nerve; a V-shaped plate for conforming with the leg'stibia to reproducibly position the band so that the electrodes arelocated over the nerve; a tilt sensor for measuring the angular positionof the lower leg; a control circuit for processing the sensor signalinformation and emitting pulses through the electrodes to stimulate theleg in response to phases of body movement; and a battery for supplyingpower to the tilt sensor, control circuit and stimulator. The disclosedband is made of stretchable, breathable material.

WalkAide™ is a commercially available FES device of InnovativeNeurotronics, Inc., and is based on the technology disclosed by Stein.The orthosis component of the WalkAide™ is a narrow band made of athermoplastic material that is molded to the limb anatomy of anindividual user by heating and softening the thermoplastic material andsubsequently fitting the contour to the contour of the underlying limbsegment. Thus the shape and size of the device and the electrodepositioning is custom-fitted to the leg of one user and individualizedfor the user. This procedure is carried out by a trained medicalprofessional.

For a clinic or rehabilitation center serving a large number of users,it would be advantageous a device that can be transferred from patientto patient hygienically and with facility. Neuroprosthetic devicesrequire a significant and time-consuming set-up procedure carried out bya trained medical professional to fit the device to the anatomy of thelimb, position the electrodes accurately over the motor point, andadjust the stimulation parameters when transferring the device toanother patient. Parts of the orthosis are in prolonged contact with theskin during a session of use, and existing devices have no provision forhygienically passing the orthosis from the leg of one patient on toanother.

Prior art orthosis-based devices for the leg such as the WalkAide™device operate with relatively small electrodes typically having adiameter of 25 mm and a surface area in contact with the skin of about4.9 cm² positioned relatively close together in the orthosis. Thisenables the orthosis to take the form of a relatively narrow band toaccommodate the small electrodes and separation. However, activation ofthe leg muscles by electrical stimulation requires typically highstimulation currents. But the stimulation current passing through theelectrode to the skin surface activates skin sensory receptors inaddition to underlying excitable motor nerve and muscle tissue and theintensity of sensory activation will depend on the intensity of thecurrent density passing through the skin surface. The level of muscleactivation is often limited in the typical patient by his individualtolerance to activation of these skin pain sensors. For these patients.it would be advantageous to reduce the sensory discomfort by loweringthe skin current density while maintaining levels of muscle activation.A further means to increase the contraction force of the activatedmuscles is to increase the distance separating the electrodes in thepair, particularly the distance along the length of the leg. This canresult in the recruitment of more muscle fibers, resulting in increasedactivated rotation torque output from the ankle joint, without thenecessity to use a high stimulation current intensity. This electrodegeometry and arrangement for increasing muscle force output and reducingsensory discomfort is too large to fit within the prior art narrow banddesign of the orthosis. To date, no orthosis exists for accommodatingsurface electrodes of such size and configuration.

Furthermore, a means for accurately positioning the electrodes along thelength of the leg becomes essential where the electrodes aresignificantly separated in this longitudinal direction, and accuratelongitudinal positioning of the orthosis becomes mandatory to avoidactivating unwanted muscles. Accommodating the large stimulationelectrodes with a larger distance separating them particularly in thelongitudinal direction requires housing these electrodes in an orthosisthat is significantly wider, extending both proximally and distallyalong the length of the leg. The wide orthosis design introduces newproblems concerned with fitting and self-placement. Moreover, the largerdimensions of the orthosis appreciably compromise the ability of theorthosis to fit the contour of the limb segment, especially during limbextensions, flexions and gait.

Also, an accurate but simple means to enable the typical stroke patientto position the height of the orthosis along the length of the leg isrequired. Prior art leg devices have used anatomical landmarks such asthe tibia as a reference to locate the device orthosis on to the leg.The wide orthosis design is difficult to locate on to the tibia.Especially in large and wide legs, the tibial crest is rather flat andconsequently is a poor anatomical landmark for accurately positioningthe orthosis and hence the electrodes circumferentially around the leg.Moreover, the longitudinal positioning along the leg is not positivelydetermined by the tibial crest.

There is therefore a recognized need for, and it would be highlyadvantageous to have, an improved FES orthosis for a neuroprostheticsystem and method that overcome the manifest deficiencies of the priorart. It would be of particular advantage to have an FES leg orthosisthat can easily and accurately be donned on the limb by patients alsosuffering from an impaired hand. It would also be of particularadvantage to have an FES leg orthosis in which an even pressure of theelectrode surface is maintained during limb extensions, flexions andgait. It would also be of particular advantage to enable greater ankletorque generation with lessening of skin sensory discomfort at theelectrode site by increasing the size and longitudinal separation of theelectrodes. It would be of further advantage for the FES orthosis to besubstantially universally adaptable to the different anthropometricvariables of limbs and to electrode positioning needs of a wide varietyof users. Finally, it would be of particular advantage to have an FESorthosis designed and configured such that the on-board stimulation unitdoes not significantly protrude outside the profile of the orthosis anddoes not impede donning and wearing clothing such as trousers over theorthosis. This is of Major significance to the stroke patient who isgenerally is challenged by donning trousers on to his plegic leg using asingle hand, and a protruding device attached to his leg may disable hisability to dress himself independently.

SUMMARY

According to the teachings of the present invention there is provided afunctional electrical stimulation orthosis for providing functionalelectrical stimulation to a limb segment of a user, the orthosisincluding: (a) an at least semi-rigid, self-retaining C-shaped frame,the frame configured to substantially envelop the limb segment, theframe including a first flexible and elongated circumferentiallyretaining element and at least a first and a second opposing flexibleand elongated circumferentially retaining elements disposed on thecircumferentially opposite side of the frame, the first retainingelement and the first opposing retaining element forming a pair ofopposing retaining elements, and (b) at least one surface electricalstimulation electrode for contacting at least one stimulation point on asurface of the limb segment, associated with, and supported by, theframe, the at least one surface electrode for electrically associating,via the frame, with a neuroprosthetic stimulator unit, so as to providefunctional electrical stimulation, wherein the opposing retainingelements are configured to be radially spring-loaded towards a center ofthe frame, such that in donning the orthosis around the limb segment,the limb segment applies a counter-pressure from within the frame,against the opposing retaining elements, such that the orthosis isfirmly and fixedly self-retained in a pre-determined position on thesurface of the limb segment.

According to further features in the described preferred embodiments,all of the flexible and elongated retaining elements are configured toconform to a contour of the surface in a substantially independentfashion, so as to maintain intimate contact with the contour.

According to still further features in the described preferredembodiments, the opposing retaining elements include at least threeflexible and elongated circumferentially retaining elements.

According to still further features in the described preferredembodiments, the orthosis further includes: (c) a locking mechanism,associated with the frame, for locking the at least one surfaceelectrical stimulation electrode at the pre-determined position on thesurface of the limb segment.

According to still further features in the described preferredembodiments, the opposing retaining elements are designed and configuredto independently respond, mechanically, to changes in the contour, so asto retain the at least one surface electrical stimulation electrodefixed against the pre-determined position on the limb segment and so asto maintain an even pressure against the pre-determined position on thesurface of the limb segment.

According to still further features in the described preferredembodiments, the semi-rigid frame includes a housing for receiving thestimulator unit.

According to still further features in the described preferredembodiments, the housing is dimensioned to envelop and hold thestimulator unit intimately and flatly against the orthosis.

According to still further features in the described preferredembodiments, the orthosis further includes: (c) the neuroprostheticstimulator unit, wherein the stimulator unit is designed and configuredto: (i) communicate with a sensor for sensing a physical parameterrelating to the limb segment, and (ii) based on a signal relating to thesensor, deliver a stimulation signal to the surface electrode.

According to still further features in the described preferredembodiments, the stimulator unit includes a radio frequency transceiverfor communicating with at least one of a stimulator control unit and thesensor.

According to still further features in the described preferredembodiments, the locking mechanism includes at least one elastic strapdesigned to extend circumferentially around and bridge between theopposite sides of the frame and to be reversibly fastened to a fasteningelement associated with the frame.According to still further features in the described preferredembodiments, the orthosis is a lower-leg orthosis, wherein an uppercontour of the orthosis is a locating surface, the locating surfaceconfigured to conform to an inferior border of a patella of the user.

According to still further features in the described preferredembodiments, the locating surface has a three-dimensional cup shape forabutting an inferior border of a patella of the user during donning ofthe orthosis.

According to still further features in the described preferredembodiments, the orthosis is designed and configured for single-handeddonning by the user.

According to still further features in the described preferredembodiments, the fastening element includes a protuberance associatedwith the frame.

According to still further features in the described preferredembodiments, the protuberance includes a housing for receiving thestimulator unit.

According to still further features in the described preferredembodiments, the at least one elastic strap terminates in a loopedhandle, the looped handle designed to be reversibly fastened to thefastening element.

According to still further features in the described preferredembodiments, the orthosis further includes: (c) the neuroprostheticstimulator unit, and (d) a housing for receiving the stimulator unit,the housing disposed on a flexible leaf on the frame, such that thehousing and the leaf are free to move as a unit, independently of theretaining elements, so as enable the retaining elements to mechanicallyrespond, substantially independently, to changes in a contour of the legsegment, even when pressure is exerted on an exterior face of thestimulator unit.

According to still further features in the described preferredembodiments, circumferentially disposed on the frame is at least onespring-loaded strip, the strip being radially spring-loaded towards acenter of the frame, such that in donning the orthosis around the limbsegment, the spring-loaded strip applies a pressure against the limbsegment, such that the orthosis is self-retained in position on the limbsegment while allowing for small adjustments to be made in positioningof the orthosis on the limb segment.

According to still further features in the described preferredembodiments, the second flexible and elongated circumferentiallyretaining element has a width, W, wherein W is within a range of about2-4.5 cm.

According to still further features in the described preferredembodiments, the second opposing retaining element has a width, W, andthe orthosis has a height, H, and wherein W is within a range of 8-60%of H.

According to still further features in the described preferredembodiments, each of the at least one surface electrical stimulationelectrode has a surface area for contacting the surface of the limbsegment, and wherein for each the electrode, the surface area is atleast 9 cm².

According to still further features in the described preferredembodiments, the surface area is at least 12 cm².

According to still further features in the described preferredembodiments, the at least one elastic strap terminates in a loopedhandle, the looped handle designed to be reversibly fastened to thefastening element, and wherein the looped handle, when fastened to thefastening element, completes a smooth and substantially non-protrudingprofile that includes the orthosis, the stimulator unit, the housing,and the looped handle, all of which together blend into a profile of aleg of the user.

According to yet another aspect of the present invention there isprovided an orthosis of for providing functional electrical stimulationto a limb segment of a user, the orthosis including: (a) an at leastsemi-rigid frame being configured to substantially envelop the limbsegment; (b) a soft inner facing for at least partially covering aninner face of the frame and for providing a comfortable interfacebetween the frame and the limb segment; (c) a first mechanical fittingassociated with the inner face of said frame, and (d) at least onesurface electrical stimulation electrode assembly associated with, andsupported by the frame, the assembly having a stimulation electrodehaving a surface for contacting at least one stimulation point on thelimb segment, and an attachment mechanism for fixing a position of theelectrode with respect to the frame, the at least one surface electrodefor electrically associating, by way of the frame, with aneuroprosthetic stimulator unit for providing a stimulation signal tothe surface electrode, and wherein the stimulation electrode assemblyhas a second mechanical fitting, complementary to the first mechanicalfitting, for reversibly attaching the stimulation electrode assembly to,and reversibly detaching the stimulation electrode assembly from, thefirst mechanical fitting.

According to still further features in the described preferredembodiments, the first and second mechanical fittings are connectorsselected from the group consisting of snaps and hook and loop fasteners.

According to still further features in the described preferredembodiments, the attachment mechanism includes an electrode base havinga surface for receiving and engaging a second side of the stimulationelectrode, the second side being opposite the first side.

According to still further features in the described preferredembodiments, the electrode base has a rim for physically defining, forthe stimulation electrode, a substantially singular position therein.

According to still further features in the described preferredembodiments, the second side of the stimulation electrode includes ahydrogel-containing surface, and wherein the surface of the electrodebase includes at least one patch of hook fasteners for securing thehydrogel-containing surface to the electrode base.

According to still further features in the described preferredembodiments, the soft inner facing is a reversibly attachable anddetachable panel.

According to still further features in the described preferredembodiments, the orthosis further includes: (e) a soft panel forcovering at least a portion of the soft inner facing, the soft panelhaving a third complementary connector for associating with a fourthcomplementary connector associated with the frame, so as to reversiblysecure the soft panel to the frame.

According to another aspect of the present invention there is providedan orthosis for providing functional electrical stimulation to a limbsegment of a user, the orthosis including: (a) an at least semi-rigidframe configured to substantially envelop the limb segment, the framehaving at least one first complementary mechanical fastener associatedtherewith; (b) at least one surface electrical stimulation electrodeassembly associated with, and supported by the frame, the assemblyhaving a surface stimulation electrode for contacting at least onestimulation point on the limb segment, the at least one surfaceelectrode assembly having an electrode base for electricallyassociating, via the frame, with a neuroprosthetic stimulator unit forproviding a stimulation signal to the surface electrode, the electrodebase having a top face for receiving the stimulation electrode, theelectrode base having a bottom face having at least one secondcomplementary mechanical fastener, the second fastener beingcomplementary to the first fastener, the first and second fastenersdesigned and configured for reversible attachment and reversibledetachment, at a plurality of locations on the frame, thereby enablingthe electrical stimulation electrode assembly to be adjustably andreversibly positioned on the frame.

According to further features in the described preferred embodiments,the electrode base is associated with a conductive element forelectrically connecting the base to the neuroprosthetic stimulator unit.

According to still further features in the described preferredembodiments, the conductive element is a first conductive complementarymechanical fastener, and wherein associated with the frame is a secondconductive complementary mechanical fastener, the first conductivefastener being complementary to the second conductive fastener.

According to still further features in the described preferredembodiments, the electrode base is loosely associated with the firstconductive fastener by means of a flexible wire, thereby enabling theelectrical stimulation electrode assembly to be adjustably andreversibly positioned on the frame in a plurality of positions,according to individual needs of the user.

According to still further features in the described preferredembodiments, the electrode base is associated with the first conductivefastener by means of a flexible wire, thereby substantially decouplingan electrical connection of the electrode assembly to the stimulatorunit from a mechanical connection of the electrode assembly to thestimulator unit, so as to enable the electrode assembly to be adjustablyand reversibly positioned on the frame in a plurality of positions,according to individual needs of the user.

According to still further features in the described preferredembodiments, the first and second fasteners include hook and loopfasteners.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, withreference to the accompanying drawings. With specific reference now tothe drawings in detail, it is stressed that the particulars shown are byway of example and for purposes of illustrative discussion of thepreferred embodiments of the present invention only, and are presentedin the cause of providing what is believed to be the most useful andreadily understood description of the principles and conceptual aspectsof the invention. In this regard, no attempt is made to show structuraldetails of the invention in more detail than is necessary for afundamental understanding of the invention, the description taken withthe drawings making apparent to those skilled in the art how the severalforms of the invention may be embodied in practice. Throughout thedrawings, like-referenced characters are used to designate likeelements.

In the drawings:

FIG. 1 is a perspective view of the inventive FES orthosis for gaitmodulation;

FIG. 2 is a perspective front view of a central, semi-rigid frame of theinventive FES orthosis of FIG. 1;

FIG. 3 is a perspective back view of the frame of FIG. 2, showing alsoan attached stimulator unit and housing;

FIG. 3A is a perspective side view of the frame of the FES orthosis ofFIG. 2, with the stimulator unit and housing removed to reveal aflexible leaf, integral to the frame, for supporting the stimulator unithousing;

FIG. 4 is a perspective view showing a tightening mechanism of theinventive FES orthosis;

FIG. 5 illustrates a side view of the donning of the device of FIG. 1 onan impaired leg;

FIG. 6 illustrates a front view of the donning of the device of FIG. 1on the impaired leg;

FIG. 7 is a perspective view showing the attachment of a neuroprostheticstimulator unit to the FES orthosis of FIG. 1;

FIG. 8 illustrates the association of the neuroprosthetic stimulatorunit with a cradle of the FES orthosis of FIG. 1;

FIG. 9 is a perspective view of an electrode assembly of the inventiveFES orthosis of FIG. 1;

FIG. 9A is a perspective view of another embodiment of the inventiveelectrode assembly;

FIG. 9B is a schematic side view of a portion of the inventive FESorthosis, showing electrical and mechanical connections between thelayers of the orthosis;

FIG. 10 is a perspective view of two electrode assemblies of FIG. 9attached to an internal soft layer of the device of FIG. 1;

FIG. 11 is a block diagram showing the main features of the electricalstimulation unit;

FIG. 12A is a front view of a detachable layer of the FES orthosis,according to one aspect of the present invention;

FIG. 12B illustrates another embodiment of the inventive detachablelayer, having hollow snap connectors for securing the detachable layerto the internal layer of the orthosis, and

FIG. 12C illustrates another embodiment of the inventive detachablelayer, in which the layer covers only a portion of the surface of theinternal layer of the orthosis;

FIG. 12D is a schematic cross-sectional side view of a slice of aportion of the inventive FES orthosis, showing some of the electricaland mechanical connections between the detachable lining and othercomponents of the orthosis;

FIG. 12E is a schematic cross-sectional side view of a slice of aportion of the inventive FES orthosis, showing some of the electricaland mechanical connections between the detachable lining and othercomponents of the orthosis, wherein the detachable lining is directlyattached to the orthosis frame;

FIG. 13A is a schematic perspective view of the electrode assembly anddetachable layer, according to another embodiment of the presentinvention;

FIG. 13B is a detailed magnification of FIG. 13A, and

FIG. 13C is a detailed, magnified, cross-sectional view of a snapconnector of the electrode assembly mechanically connected to acomplementary connector on the detachable layer.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is an improved functional electrical stimulation(FES) orthosis and method, and more particularly, an FES orthosis forusers suffering from gait problems such as drop foot. The orthosis caneasily be donned on the leg, even by patients suffering from an impairedhand.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not limited in its applicationto the details of construction and the arrangement of the components setforth in the following description or illustrated in the drawing. Theinvention is capable of other embodiments or of being practiced orcarried out in various ways. Also, it is to be understood that thephraseology and terminology employed herein is for the purpose ofdescription and should not be regarded as limiting.

Referring now to the drawings, FIG. 1 is a perspective view of theinventive FES gait modulation orthosis 150; FIG. 2 and FIG. 3 areperspective front and back views, respectively, of the central,semi-rigid frame 50 of the FES orthosis. It can be seen from thesedrawings that FES orthosis 150 includes three layers: central frame 50,which is at least semi-rigid, an internal soft layer 114 covering theinner facing of frame 50, and an external soft layer 60 covering theouter facing of frame 50. Additionally, orthosis 150 includes aneuroprosthetic stimulation unit 46, as well as stimulation electrodeassemblies (shown in detail in FIG. 9 and described hereinbelow).

As used herein in the specification and in the claims section thatfollows, the term “limb segment” refers to a limb segment including aportion of the upper or lower arm, or the upper or lower leg.

As used herein in the specification and in the claims section thatfollows, the term “envelop”, “enveloping”, and the like, with regard toa limb segment and an article therefor, refers to an article thatsubstantially surrounds and covers at least one half the circumferenceof a limb segment.

As used herein in the specification and in the claims section thatfollows, the term “reversible”, “reversibly”, and the like, with respectto attachment and/or detachment of an element or assembly, refers to anon-destructive, repeatable attachment and/or detachment. The term“reversible attachment”, “reversibly attached”, and the like, withrespect to a soft layer associated with the frame of the orthosis,further refers to a reproducible positioning of the soft layer, withrespect to the frame, each time the soft layer is reattached.

As used herein in the specification and in the claims section thatfollows, the term “inner face” refers to at least one of: the face ofthe detachable layer for contacting the surface of the limb segment ofthe user, and the face of the soft inner layer disposed within thecentral frame. Thus, in an orthosis in which there is no detachablelayer, the term “inner face” refers to the face of the soft inner layerdisposed within the central frame.

Central frame 50 is ergonomically configured to at least partiallyenvelop the limb segment, more preferably, to surround at least ⅔ of thecircumference of the limb segment, and most preferably, to substantiallyenvelop the limb segment completely. As shown in FIG. 2, frame 50includes at least one circumferentially retaining element pair 12 fortightly enveloping the limb. Retaining element pair 12 includesopposing, flexible and elongated members, such as flexible, elongatedmember 14 and flexible, elongated member 10 c. Preferably, retainingelement pair 12 includes flexible and elongated members that aresubstantially directly opposite, such as member 14 and member 10 d.

In addition, flexible, elongated members 14, 10 a-d are flexible, andspring-loaded towards the limb segment. Hence, in increasing thediameter of central frame 50, the pressure applied from within frame 50must overcome the resistance of the spring-loaded retaining element pair12, as well as the resistance of additional flexible and elongatedmembers 10 a-10 c. Consequently, when orthosis 150 is donned byexpanding frame 50 around the limb segment, orthosis 150 is tightly heldin the desired position by retaining element pair 12 and additionalmembers 10 a-10 c.

Preferably, spring-loaded metal strips 37 a, 37 b are disposed aroundthe circumference of frame 50, to augment the spring-loading action offlexible, elongated members 14, 10 a-d, and to maintain the efficacy ofthe spring-loading action over the lifetime of orthosis 150.

Central frame 50 is preferably configured to have one individualelongated member 14 on a first side of retaining element pair 12, andtwo to four individual elongated members 10 a to 10 d on the opposingside, more preferably, three elongated members, and most preferably, atleast four, as shown in FIGS. 2 and 3. In this case, frame 50 resemblesan open hand where individual retaining members 10 a to 10 d resemblefingers, and individual retaining member 14 resembles a thumb.

While inventive FES orthosis 150 can be designed to have two or moreindividual retaining member on each side, the inventors have found thathaving a single, narrow retaining member (such as retaining member 14)on one of the sides facilitates both the donning process and the doffingprocess. Preferably, each single, narrow retaining member 14, 10 a-d hasa width of 1.0-6 cm, more preferably, 2-4.5 cm, and most preferably,2.5-3.5 cm. Within these width ranges, this single, narrow retainingmember is wide enough to grip the limb segment, and narrow enough toenable facile donning of the orthotic device. With respect to the heightof the orthotic device, the single, narrow retaining member has a widthW within a range of 8-60% of the height of the orthotic device, morepreferably, 10-35%, and most preferably, 15-30%. Above these ranges,central frame 50 acts in a more rigid fashion during the donning processand the doffing process.

Disposed between retaining members 10 a to 10 d are gaps 18 a to 18 c,as shown in FIG. 2. Gaps 18 a to 18 c enable elongated members 10 a-10 dto conform in substantially independent fashion to the contours of thelimb segment, both when the limb segment is static and dynamic. Itshould be emphasized that various limb segments exhibit large profilechanges, especially during articulations of the neighboring joints,along with activation of the muscles of the particular limb segment.

Thus, the above-described arrangement enables a superior enveloping ofthe limb segment by frame 50, and serves to effectively disperse thepressure and strains on the limb tissue, retaining thereby the naturalprofile and geometry of the limb tissue and muscles. The dispersion ofpressures via flexible members 10 a to 10 d also enables an orthosis 150of a particular diameter and contour to accommodate a wide variety oflimb diameters and profiles.

Significantly, the open-hand shape of central semi-rigid frame 50 alsoallows the limb to be firmly gripped and retained in exact position byFES orthosis 150 during donning of the device, until final locking oforthosis 150, which will be described hereinbelow.

When FES orthosis 150 is donned on a leg, the above-describedarrangement is particularly suitable for enabling the orthosis to adaptto anatomical changes with time, as well as to changes due to thecontraction and expansion of the muscles during walking, whilemaintaining the stimulation electrode in accurate position against thecontact points on the leg segment, and with even pressure.

FIG. 3A is a perspective side view of central frame 50, revealing aflexible leaf or plate 27, integral to frame 50, for supporting thestimulator unit housing or cradle 30 (not shown). Flexible leaf 27 ispreferably attached to frame 50 solely on one side (or on a portion ofone side), such that pressure exerted on stimulation unit 46 (not shown)is substantially absorbed solely by flexible leaf 27. This enables thesurface electrical stimulation electrodes to maintain a fixed position,and with substantially even pressure, against a pre-determined positionon the surface of the limb segment, even when stimulation unit 46 isknocked, pushed, or pulled. In FIG. 3A, flexible leaf 27 is connected toframe 50 solely by two narrow necks 27 a, b, so as to minimize pressuresand strains on frame 50 due to stimulation unit 46.

When suitably positioned below the knee, (see also FIGS. 5 and 6),orthosis 150 provides electrical stimulation to the contact pointsoverlying the peroneal nerve and the tibialis anterior muscle, so as tomodulate the gait. To guide the positioning, central frame 50 preferablyincludes an upper locator 22, and a lower locator 26. Upper locator 22preferably has the form of a three-dimensional inverted arch, contoured,so as to conform to the inferior border of the tuberosity of the patellaand to the characteristic anatomical recesses on each side thereof. Theedge of the device is made of elastomeric material to provide comfortwhen positioned on the limb, and to improve the stability of FESorthosis 150 on the limb segment.

Upper locator 22 includes a molding extending from semi-rigid frame 50so as to abut the inferior border of the patella, while lower locator 26is designed to conform to the characteristic anatomical shape of theinferior surface of the tibial crest. When donning FES orthosis 150 onthe leg, locator 22 assists both in the accurate longitudinal placementof orthosis 150 along the long axis of the lower leg segment, and in therotational orientation about the long axis of the leg segment, as willbe described in greater detail hereinbelow. Locator 26 assists in therotational orientation about the long axis of the leg segment.

After exact positioning of FES orthosis 150 on the stimulation pointshas been achieved, orthosis 150 is firmly secured and locked on to thelimb segment by a robust fastening arrangement 34 (shown in FIGS. 1 and3), which is firmly associated at a first end, with central frame 50,and ends in a handle 54 at the opposite end. Fastening arrangement 34further includes substantially parallel, elastic modular straps 34 a and34 b, connecting between the first end and handle 54. Elastic modularstraps 34 a and 34 b are designed such that during donning, straps 34 aand 34 b wrap circumferentially around the limb segment, to tightly lockFES orthosis 150 in place around the segment. The locking may beeffected by fastening handle 54 to stimulator unit housing or cradle 30.Various exemplary alternatives for this fastening are providedhereinbelow.

Each of elastic straps 34 a and 34 b is equipped with an adjustmentbuckle 38 (see FIG. 5), so as to allow different degrees of tighteningaccording to the contour of the leg segment and according to the needsof individual patients.

As previously mentioned, central frame 50 is covered by an externallayer 60, which is made of a soft, preferably aesthetic material.Elastic straps 34 a and 34 b emerge through openings 42 a and 42 b inexternal layer 60, as shown in FIG. 4. This configuration eliminates orgreatly reduces the distortion of central frame 50 during the securingof orthosis 150 to the leg.

Handle 54 is preferably made of an elastomeric material that imparts aflexible nature to handle 54. Preferably, handle 54 has a generallyloop-like shape (hollow, with a rectangular or oval perimeter), so as tofit around stimulator cradle 30, or around any other connecting point orprotuberance extending from frame 50, thereby securely locking orthosis150 in place over the limb segment. Once positioned around stimulatorcradle 30, handle 54 helps to protect stimulation unit 46 around thesides thereof, thereby providing stimulator cradle 30 and stimulationunit 46 with a smooth and unobtrusive profile. This is particularlyimportant because knocks and pressures delivered to the surfaces ofstimulation units of the prior art, in addition to being unpleasant forthe user, can compromise the substantially even pressure applied by thesurface electrode to the surface of the limb segment. The streamlinedprofile also facilitates rolling a pant leg past orthosis 150.

Fastening arrangement 34 is modular, can be easily detached fromorthosis 150, and can be manufactured in several sizes.

FIGS. 5 and 6 illustrate the donning—and subsequent locking—of FESorthosis 150 on an impaired leg. For positioning orthosis 150, whileseated, it is preferable for the user to partially extend the lower leg,as shown in FIG. 5, such that the protuberance of the patella 58 isclearly defined. Subsequently, orthosis 150 is placed on the leg, suchthat upper locator 22 is juxtaposed against the lower facing of patella58. Lower locator 26 should then be centered around tibial crest 62.Orthosis 150 grips the leg gently, but firmly enough to keep orthosis150 in place, even if the user releases his grip as in the case, interalias of hemiplegic users. Subsequently, the securing of orthosis 150 iscompleted by fastening arrangement 34.

An alternative donning procedure is to place FES orthosis 150 along thetibial crest 62, a few centimeters below patella 58, and then to gentlyslide orthosis 150 up the calf until upper locator 22 abuts againstpatella 58. After orthosis 150 grips the leg segment so as to retain thedesired position, locking is achieved by grasping handle 54 with thefingers of the opposite hand from the leg with orthosis 150. The thumbis placed on cradle 30, to hold orthosis 150 in place, and preventingsliding down or rotation, while the hand is closed so that the loop ofhandle 54 fits snugly around cradle 30. Alternatively, four fingers ofthe hand opposite to the leg with orthosis 150 are slipped throughhandle 54, grasping the handle close to cradle 30. The fingers then curlonto the attachment point of cradle 30 and lever handle 54 into placewhile allowing handle 54 to slip off the fingers. Once handle 54 islocked in place around cradle 30, the tension of fastening arrangement34 firmly holds orthosis 150 around the limb segment of the user, evenduring aggressive movement of the limb.

FES orthosis 150 is doffed by releasing handle 54 from cradle 30 andpulling orthosis 150 away from the leg segment. It should be emphasizedthat both donning and doffing may easily be performed, unassisted andusing a single hand, by hemiplegic patients.

Members 10 a to 10 d and member 14 of central frame 50 are preferablymade of a polymeric material that provides flexibility and spring-likecharacteristics to orthosis 150. This combination of structure andmaterials provide the following features to orthosis 150:

-   -   1. Facile placement on the leg using a single hand.    -   2. Spring-loaded retention or gripping of orthosis 150 in proper        position prior to and during locking orthosis 150 in position.        Both the facile placement of the orthosis and the self-retaining        grip of the orthosis on the leg enable patients suffering from        an impaired hand to effectively don the device.    -   3. Accurate locating and relocating of the stimulating electrode        assemblies.    -   4. After locking of orthosis 150 on the limb, the structure and        materials of these members prevent random movement and migration        of orthosis 150, even during limb extensions, flexions and gait.    -   5. Uniform dispersion of the pressure and strains to the limb        tissue, thus retaining the natural profile and geometry of the        limb tissue and muscle.    -   6. Uniform pressure of the electrodes against the surface of the        limb segment.

Referring now to FIGS. 1, 3 and 7, stimulator unit 46 is associated withorthosis 150 by means of cradle 30, which is a receptacle integratedonto the external surface of central frame 50.

Cradle 30 is advantageously designed to have concave edges for receivinga thumb during the donning procedure. Placing the thumb on the edges ofcradle 30 enables the formation of a counter-force for urging handle 54towards cradle 30. The backside of cradle 30 has a concavity similar tothat of central frame 50, such that the overall contour can adapt to thecontour of the limb segment.

Stimulator unit 46 is small and has a thin profile, so as to minimallyprotrude from the surface of orthosis 150, and is lightweight, to avoidsuperfluous weight on the impaired leg.

Stimulator unit 46, as shown in FIGS. 7 and 8, is electrically connectedto cradle 30 by connectors 66 and 70 disposed on stimulator unit 46 andon cradle 30, respectively. In one preferred embodiment, theseconnectors are complementary connectors. As shown, connector 66 is acomplementary female snap, and connector 70 is a corresponding malesnap. Stimulator unit 46 is mechanically connected to cradle 30 bycomplementary mechanical connectors 74 and 78. In the embodiment shownin FIG. 8, these connectors are male latch 74 disposed on an edge ofcradle 30, and a female latch receiver 78 disposed on an edge ofstimulator unit 46. An additional notch 82 in cradle 30 allows pullingstimulator unit 46 with a finger or thumb to release it from cradle 30.These connective features enable facile detaching and reattaching ofstimulator unit 46 from, or to, cradle 30 using a single hand.

Referring now to FIG. 9, FIG. 9B and FIG. 10, FIG. 9 is a perspectiveview of an electrode assembly 90 of inventive orthosis 150 (not shown).Electrode assembly 90 includes a surface electrode 94, an electrode base98, and complementary conductive connectors 102 and 106. Electrodeassembly 90 further includes a conductive wire 110, which, at a firstend, is mechanically connected to electrode base 98 so as to provide anelectrical connection to connector 106. Conductive wire 110 terminatesat a second end with a complementary conductive connector 122, whichmechanically connects electrode assembly 90 to central frame 50 (asshown below in FIG. 9B), and electrically connects electrode assembly90, via central frame 50, to stimulator housing 30 (also shown below inFIG. 9B).

In the exemplary embodiment shown in FIG. 9, complementary connector 102is a male snap connector associated with surface electrode 94, whilecomplementary connector 106 is a female snap connector connected toelectrode base 98. Both surface electrode 94 and electrode base 98 aremade of flexible materials that enable them to conform to the limbtissues.

Electrode base 98 is preferably concave-shaped, such that the connectionbetween complementary connector 102 of surface electrode 94 andcomplementary connector 106 of electrode base 98 is recessed within arecess, thereby preventing excessive local pressure of the snaps 102 and106 on the underlying skin. The concave, 3-dimensional shape of the topsurface of electrode base 98 also provides a substantially even contactpressure of surface electrode 94 to the skin.

Surface electrode 94 preferably has a large surface area, with respectto many FES leg devices of the prior art, which serves to assuagediscomfort from the electrical stimulation. The surface area of surfaceelectrode 94 is preferably at least about 9 cm², more preferably atleast about 12 cm², and even more preferably, at least about 15 cm². Insome cases, the surface area of surface electrode 94 is as much as about20 cm². It is presently preferred that the surface area of surfaceelectrode 94 is within a range of 12-20 cm². By sharp contrast, thesurface area of each surface electrode of the prior art devices such asthe WalkAide™ device is less than 5 cm².

In contrast to prior art FES leg devices, the electrode separation inthe FES orthosis of the present invention is preferably as large asanatomical constraints permit, particularly in the direction along thelength of the limb. The distance between electrode centers is at leastabout 5 cm and the longitudinal separation is at least about 3 cm, andpreferably at least 3.5 cm.

FIG. 9A is a perspective view of another embodiment of an electrodeassembly 90A of inventive orthosis 150 (not shown). Electrode assembly90A includes a surface electrode 94A, an electrode base 98A, and a wire110, which terminates with complementary connector 122. In the exemplaryembodiment shown in FIG. 9A, surface electrode 94A has first and secondfaces 95, 97 made of hydrogel or any another conductive, adhesivematerial known in the art for use in surface electrodes. First face 95is for flexibly adhering to the skin of the user, while the oppositesecond face 97 is for adhering to a top face 99 of electrode base 98A.On top face 99 is disposed a conductive region 106A, for electricallyconnecting with second face 97. Preferably, top face 99 of electrodebase 98A is also provided with a rim 101 for tightly receiving surfaceelectrode 94A, such that the relative position of electrode 94A andelectrode base 98A is uniquely defined and determined. The connection ofelectrode 94A and electrode base 98A may be further enhanced bydisposing, on top face 99 of electrode base 98A, patches 103 of hookfasteners (e.g., plastic Velcro® hooks), which surprisingly hold on tothe substantially flat, hydrogel surface of second face 97.

Substantially as described above with respect to FIG. 9, conductive wire110 is mechanically connected to electrode base 98 so as to provide anelectrical connection to conductive region 106A.

The relationship between electrode assembly 90 and internal soft layer114, shown in FIG. 10, is also relevant for the alternative embodimentpresented in FIG. 9A and described hereinabove. Electrode base 98 isattached to internal layer 114 by complementary connectors 117 and 117a, preferably hook and loop fasteners such as Velcro®, which are bestseen in FIG. 9 b.

The electrical connections are made as follows: complementary connector122 connects to a complementary connector 123, which is disposed in afixed position on internal layer 114 or on central frame 50. Electricalstimulation is achieved by directing a current from stimulator unit 46(not shown), via connector 70 disposed on housing 30, through frame 50and internal layer 114, to connector 123, and ultimately, to electrodeassembly 90A and stimulator housing 30 with connector 123.

In the exemplary embodiments shown, complementary connector 122 is aconductive male snap connector, and complementary connector 123 is aconductive female snap connector.

It will be appreciated that the design of electrode base 98 and thedesign of connectors 122 and 123 enable a wide range of positioning ofeach electrode assembly 90. Unlike various prior art devices, theposition of electrode 94 is not limited to a position in which electrode94 physically touches a conductive element fixed in the body of theorthosis (such as connector 123). Rather, the position of electrode 94is substantially decoupled with respect to such fixed conductiveelements. Wire 110 should be long enough to enable the full range ofpositioning.

In addition, the above-described design enables the clinician to exactlydefine the position of each electrode assembly 90 in a first step, andthen, in a second step, to attach the assembly to FES orthosis 150 bymeans of complementary connectors 122 and 123. Thus, during the initialsetup procedure, the clinician needs to position solely the surfaceelectrodes or electrode assemblies (e.g., electrode assembly 90A)—andnot the entire orthosis 150—on the stimulation points of the muscles tobe activated. In order to define the exact position, the clinicianactivates the electrodes, which can electrically be connected directlyto stimulator unit 46. Subsequently, the clinician connects each surfaceelectrode 94 to the respective electrode base 98 prior to donningorthosis 150 on the leg and prior to attaching each electrode base 98 tointernal layer 114 or to central frame 50. Once orthosis 150 has beendonned, each electrode base 98 attaches, by means of complementaryconnectors 117 and 117 a (shown in FIG. 9B), to internal layer 114 oforthosis 150.

Stimulation by means of the two electrode assemblies 90, illustrated inFIG. 10, produces dorsi-flexion of the foot. To ensure electricalcontact between surface electrode 94 and the skin surface, surfaceelectrode 94 may be smeared by conductive gel or hydrogel or covered bya cloth pad that has been soaked in a conductive liquid such as water.The face of surface electrode 94 for contacting the skin mayadvantageously be a flexible hydrogel layer.

Electrode assemblies 90 conform to the three-dimensional shape of theunderlying limb, and adapt their shape during limb articulations andmuscle contractions. Electrode base 98 and surface electrode 94, whichare essentially elastic, lie pressed between internal soft layer 114 andthe skin surface, such that a minimal resistance is supplied to thechanging limb geometry.

Referring now to FIG. 11, stimulator unit 46 is electrically connectedwith at least one stimulation electrode, such as surface electrode 94.Stimulator unit 46 is preferably powered by a rechargeable battery 220that is electrically connected to an internal power supply 222. Powersupply 222 supplies power to a high-voltage circuit 224 feeding intostimulation circuit 226. Preferably, stimulator unit 46 communicateswith a stimulator control unit and/or a limb or motion sensor (describedhereinbelow) by means of a radio frequency (RF) transceiver 228. Powersupply 222 supplies power at a lower voltage to RF transceiver 228, andto a digital circuit 230 interfacing between RF transceiver 228 andstimulation circuit 226.

As used herein in the specification and in the claims section thatfollows, the term “radio frequency” refers to electromagnetic waves,preferably having a frequency within the radio frequency range. Thecurrently preferred range is 2400-2483.5 GHz.

During operation, the battery-operated control unit maintains two-waycommunication with stimulator unit 46.

The control unit enables to switch on the device, select the operatingmode of the device (gait mode, training mode, or returning to standbymode), and adjust the intensity of stimulation and volume of an audioalert.

Additionally, each of the system components (FES orthosis 150, controlunit and foot sensor) is preferably represented by graphic icons on thecontrol unit. LEDs of different colors emit light under the relevanticon so as to indicate attention-requiring events such as low battery ora malfunction of any individual component. Other LEDs indicatestimulating or resting, stimulation intensity, or training mode.

The control unit preferably has an audio alert that produces an audiosignal so as to alert the user when: the system is first switched on, abutton has been pressed, a mode has been selected, the battery is low,radio communication between components of the device is lost, or, otherfaults requiring the attention of the user have occurred.

The control unit may be waist-mounted, hung by means of a neck strap, ormounted by an in-pocket hold.

The foot sensor unit may be any of various foot sensor units known inthe art, including a force sensor disposed underneath the foot of auser, a tilt sensor, etc.

FIGS. 12A-12E schematically depict another aspect of the presentinvention. FIGS. 12A and 12B show a front view of a personal panel ordetachable layer or liner 118 for attaching to the orthosis, either tointernal soft layer 114, as shown in a schematic side cross-sectionalview of a slice of the orthosis in FIG. 12D, or directly to frame 50, asshown in the identical view in FIG. 12E.

Detachable layer 118 preferably has, substantially, the shape ofinternal soft layer 114. Detachable layer 118 is soft, so as to providea comfortable feel on the skin surface of the user, but is provided withsufficient rigidity to maintain the alignment of each electrode assembly90 and to make it easier to position detachable layer 118 to theorthosis. Suitable materials for detachable layer 118 include variousnon-woven materials such as Nordenia™ loop. Detachable layer 118preferably has a top facing 139 having a plurality of complementaryconnectors 141, such as loop fasteners, disposed on the surface.

Detachable layer 118 may include the compatible electrical connectors ofinternal layer 114. Thus, detachable layer 118 may include male snapconnectors 124 on a back surface 121 facing FES orthosis 150 andcomplementary connectors such as female snap connector 123 on top facing139, for receiving complementary connector 122 (shown in FIGS. 9, 9A,and 9B) and described hereinabove. In this arrangement, detachable layer118 is attached by the clinician to internal layer 114, or to anotherportion of the orthosis, such as frame 50, by means of snap connectors124.

This provides the requisite electrical contact, and ensures accurate,singular, repeatable positioning and fixing of detachable layer 118 ontointernal layer 114 and/or with respect to frame 50. Alternatively, backsurface 121 has at least one patch 129 of hook or loop connectors thatfix detachable layer 118 to internal layer 114. In FIG. 12A, by way ofexample, patch 129 includes hook connectors.

In another preferred embodiment, shown in FIG. 12B, detachable layer 118includes holes 138, which are advantageously disposed to line up betweencomplementary male connectors 122 of electrode assembly 90 andcomplementary female connectors 123 on internal layer 114, such thatconnector 122 connects electrode assembly 90—mechanically andelectrically, to stimulator unit housing 30.

It must be emphasized that the repositioning of detachable layer 118 onFES orthosis 150, for a particular individual, restores accurate,substantially repeatable positioning of the electrode assemblies 90,even when FES orthosis 150 is a standard, universal unit that has notbeen adapted to the needs of that individual. Thus, in sharp contrast toprior art devices, inventive detachable layer 118 enables the clinicianto use a single FES orthosis 150 for treating many users in the clinic.An individual detachable layer 118 is dedicated for a particular user.Each particular user undergoes a pre-fitting session with the clinician,so as to customize the electrode positioning for the needs of that user.Subsequently, detachable layer 118 is used repeatedly in future clinicalsessions of the user. The clinician, who works with many users each day,simply removes the pre-fitted internal soft layer belonging to theprevious user and attaches the pre-fitted internal soft layer belongingto the current user. The detachable layer also serves as a hygieniclayer where the device is shared between users.

The replacement of the detachable layer 118, with no need to relocatethe electrode assemblies 90 for each patient, enables the clinician toprovide efficient, effective treatment to numerous orthosis users in ashort period of time. Detachable layer 118 is preferably disposable.Alternatively, detachable layer 118 is washable.

According to another preferred embodiment of the present invention,shown schematically in FIG. 12B, a hollow snap connector 134, which ispreferably an annular or oval hollow snap connector, is associated witha perimeter of hole 138 of detachable layer 118. Hollow snap connector134 accurately and reliably snaps into a corresponding hole or recess135, thus ensuring that detachable layer 118 is tightly attached tointernal layer 114, and is exactly positioned in the same location uponeach application. In addition, hollow snap connector 134 also serves formechanically attaching complementary connector 122 of electrode assembly90 to internal layer 114, via detachable layer 118.

Hollow snap connector 134 can be made of a plastic, flexible materialsuch as PVC.

It should be appreciated that detachable layer or liner 118 may alsohave a shape other than the contour of internal layer 114. For example,detachable layer 118 may cover only a portion of the surface of orthosis150, as shown in FIG. 12C. FIG. 12C also shows electrode base 98 affixedto detachable layer 118.

FIGS. 12D and 12E, described briefly hereinabove, show some of the mainelectrical and mechanical connections between detachable layer 118 andother components of the orthosis, wherein, in FIG. 12D, detachable layer118 is attached to central frame 50 and to internal layer 114, andwherein, in FIG. 12E, layer 118 is directly attached to central frame50.

In FIG. 12E, a complementary connector such as hollow snap connector134, is disposed on detachable layer 118. Hollow snap connector 134accurately and reliably snaps into a corresponding hole or recess 135disposed in central frame 50, so as to directly connect detachable layer118 to central frame 50. This also ensures that detachable layer 118 istightly associated with internal layer 114, and that detachable layer118 is exactly positioned, with respect to central frame 50, in the samelocation upon each application.

As described hereinabove with reference to FIG. 12A, back surface 121 ofdetachable layer 118 preferably has at least one area or patch 129 ofcomplementary connectors (e.g., hook or loop connectors) that fixdetachable layer 118 to internal layer 114 (via complementary connectors117 a).

The description of the attachments of FIG. 12D largely applies to thoseof FIG. 12E. In FIG. 12E, however, detachable layer 118 is juxtaposedagainst central frame 50, consequently, patch 129 of complementaryconnectors on back surface 121 is configured to fix detachable layer 118to central flame 50 by means of complementary connectors 117 b.

With reference to FIGS. 13A-C, and FIGS. 12D-E, FIG. 13A is a schematicperspective view of electrode assembly 90 and detachable layer 118,according to another embodiment of the present invention. As above,detachable layer 118 is equipped with hollow snap connector 134, which,as shown and described hereinabove, is configured to accurately andreliably snap into a corresponding complementary recess 135 disposed incentral frame 50, so as to directly connect detachable layer 118 tocentral frame 50.

A complementary conductive connector 222 of electrode assembly 90 has aconductive snap 222B (shown in FIG. 13C) designed to pass through a holesuch as hole 138 of hollow snap connector 134, and into a complementaryarea 135 a of complementary recess 135 so as to both mechanically andelectrically connect electrode assembly 90 to central frame 50. Theperimeter of complementary conductive connector 222 has fins orprotruding elements 222A, for snap connecting into the complementarycontour of hollow snap connector 134.

Thus, hollow snap connector 134 mechanically connects to complementaryrecess 135, complementary conductive connector 222 mechanically connectsto hollow snap connector 134 by means of protruding elements 222A, andcomplementary conductive connector 222 electrically connects tocomplementary recess 135 by means of conductive snap 222B.

It should be emphasized that complementary conductive connector 222 canbe directly attached to complementary recess 135 when no personal panelis used in the orthosis.

Although the invention has been described in conjunction with specificembodiments thereof, it is evident that many alternatives, modificationsand variations will be apparent to those skilled in the art.Accordingly, it is intended to embrace all such alternatives,modifications and variations that fall within the spirit and broad scopeof the appended claims.

What is claimed is:
 1. An apparatus, comprising: a first orthosis layerconfigured to substantially envelop a portion of a limb, the firstorthosis layer including a retention portion and a mounting portion, theretention portion configured to retain the first orthosis layer aboutthe portion of the limb, the mounting portion configured to be coupledto an electrical stimulator; a second orthosis layer coupled to an innersurface of the first orthosis layer, the second orthosis layerconfigured to be coupled to a surface electrode, the first orthosislayer and the second orthosis layer collectively configured such thatthe surface electrode is disposed at a predetermined position overlyinga peroneal nerve of the limb when the first orthosis layer and thesecond orthosis layer are disposed about the portion of the limb; and aconnector assembly configured to electrically couple the electricalstimulator to the surface electrode, at least a portion of the connectorassembly configured to be disposed within a connector opening defined byat least one of the first orthosis layer or the second orthosis layer.2. The apparatus of claim 1, wherein: the first orthosis layer includesa locator configured to identify at least one of a longitudinal positionor a rotational position of the first orthosis layer relative to theportion of a limb.
 3. The apparatus of claim 1, wherein thepredetermined position is adjacent the peroneal nerve when the firstorthosis layer is disposed about the portion of the limb such thatelectrical stimulation transmitted to the predetermined position via thesurface electrode results in dorsiflexion of a foot.
 4. The apparatus ofclaim 1, wherein the retention portion includes a first member and asecond member, an end portion of the first member spaced apart from anend portion of the second member, the first member and the second memberconfigured to exert a force about the portion of the limb when the firstorthosis layer is disposed about the portion of the limb.
 5. Theapparatus of claim 1, wherein the retention portion is constructed froma semi-rigid material, the retention portion configured to partiallysurround the portion of the limb.
 6. The apparatus of claim 1, whereinthe retention portion includes a first member and a second member, anend portion of the first member spaced apart from an end portion of thesecond member to define an opening through which the portion of the limbis disposed when the first orthosis layer is being donned, the retentionportion including a fastening strap configured to be coupled across theopening after the first orthosis layer is disposed about the portion ofthe limb.
 7. The apparatus of claim 1, further comprising: a fasteningstrap configured to removably couple the first orthosis layer to theportion of the limb, a first portion of the fastening strap fixedlycoupled to the first orthosis layer, a second portion of the fasteningstrap configured to be disposed about the electrical stimulator.
 8. Theapparatus of claim 1, wherein the second orthosis layer includes anelectrode base having a hook and loop fastener to reversibly couple thesurface electrode to the second orthosis layer.
 9. The apparatus ofclaim 1, wherein the mounting portion includes a connector configured tobe matingly coupled to a complementary connector of the electricalstimulator to couple the mounting portion to the electrical stimulator.10. The apparatus of claim 1, wherein the mounting portion includes acradle defining a recess configured to receive the electrical stimulatorto couple the mounting portion to the electrical stimulator.
 11. Anapparatus, comprising: a frame assembly configured to substantiallyenvelop a portion of a limb, the frame assembly including a retentionportion and a cradle, the retention portion configured to retain theframe assembly about the portion of the limb, the cradle defining arecess configured to receive an electrical stimulator to couple theelectrical stimulator to the frame assembly; an electrode base coupledto an inner surface of the frame assembly, the electrode base configuredto couple a surface electrode to the inner surface, the frame assemblyconfigured such that the electrode base is disposed at a predeterminedposition relative to the portion of the limb when the frame assembly isdisposed about the portion of the limb; a connector assembly configuredto electrically couple the stimulator to the electrode base, at least aportion of the connector assembly disposed within a connector openingdefined by the frame assembly; and a fastening strap configured toremovably couple the frame assembly to the portion of the limb, a firstportion of the fastening strap fixedly coupled to the frame assembly, asecond portion of the fastening strap configured to be coupled to anouter surface of the cradle when the frame assembly is coupled to theportion of the limb.
 12. The apparatus of claim 11, wherein thefastening strap includes a loop member configured to be coupled to theframe assembly.
 13. The apparatus of claim 11, wherein the predeterminedposition is adjacent at least one of a nerve or a muscle when the frameassembly is disposed about the portion of the limb such that electricalstimulation transmitted to the predetermined position via the surfaceelectrode results in dorsiflexion of a foot.
 14. The apparatus of claim11, wherein the predetermined position overlies a peroneal nerve. 15.The apparatus of claim 11, wherein the retention portion includes afirst member and a second member, an end portion of the first memberspaced apart from an end portion of the second member, the first memberand the second member configured to exert a force about the portion ofthe limb when the frame is disposed about the portion of the limb. 16.The apparatus of claim 11, wherein the cradle defines a notch, a portionof the electrical stimulator being accessible via the notch when theelectrical stimulator is disposed within the recess.
 17. An apparatus,comprising: a frame assembly configured to substantially envelop aportion of a limb, the frame assembly including a retention portion anda mounting portion, the retention portion including a first member and asecond member, an end portion of the first member spaced apart from anend portion of the second member to define an opening through which theportion of the limb is disposed when the frame assembly is being donned,the mounting portion configured to be coupled to an electricalstimulator; an electrode base coupled to an inner surface of the frameassembly, the electrode base configured to couple a surface electrode tothe inner surface, the frame assembly configured such that the electrodebase is disposed at a predetermined position overlying a peroneal nervewhen the frame assembly is disposed about the portion of the limb; aconnector assembly configured to electrically couple the stimulator tothe electrode base, at least a portion of the connector assemblydisposed within a connector opening defined by the frame assembly; and afastening strap configured to be coupled across the opening to securethe frame assembly to the portion of the limb, the first member and thesecond member collectively configured to substantially retain the frameassembly about the portion of the limb before the fastening strap iscoupled across the opening.
 18. The apparatus of claim 17, wherein afirst portion of the fastening strap is fixedly coupled to the frameassembly and a second portion of the fastening strap is configured to bedisposed about the electrical stimulator.
 19. The apparatus of claim 17,wherein the frame assembly includes a semi-rigid outer member and aninner layer coupled to an inner surface of the outer member, theelectrode base coupled to an inner surface of the inner layer.
 20. Theapparatus of claim 17, wherein the mounting portion includes a cradledefining a recess configured to receive the electrical stimulator tocouple the mounting portion to the electrical stimulator.
 21. Theapparatus of claim 17, wherein the mounting portion includes a cradledefining a recess and a notch, the recess configured to receive theelectrical stimulator to couple the mounting portion to the electricalstimulator, a portion of the electrical stimulator being accessible viathe notch when the electrical stimulator is disposed within the recess.22. The apparatus of claim 17, wherein the frame assembly includes asemi-rigid outer member configured to maintain a C-shape to retain theframe assembly about the portion of the limb before the fastening strapis coupled across the opening.